Phonograph diaphragm



E. F. MATTAUSCH PHONOGRAPH DIAPHRAGM Filed May 22 mgl.

' INVENTOR f'. F.' Maauscl?.

ATTORNEYS Patented Aug. 14, 1923.

UNITED STATES EDWIN F. MATTAUSCE, OF BOSALIA, WASHINGTON;

IPHONOGRAPH DIAPHRAGM.

Application filed May 22,' 1922. Serial No. 562,7/23.v

To all 'whom z't may concern.

Be it known that I, EDWIN F. MATTAUSCH, a citizen ofA the United' States, residin at Rosalia, in the county of Whitman and tate of Washington, have invented certain new and useful Improvements in Phonograph Diaphragms, of'whi'ch the following is a specification. i

My invention relates to the art of sound recording and reproducing apparatus and moreespecially to vibratory diaphragms of the kind particularly employed in phonographs. It is an object of the invention to produce a diaphra In which will ive softer tones, uniformly istinct, regard ess of the kind of material used in the horn and .tone

arm.

.Again it is an object of the invention to provide a diaphragm of a simple and effective construction that can be manufactured at minimum expense, of such material as will enable the diaphragm to respond effectively to sound vibrations without being itselfy influenced by atmospheric changes.

The invention is illustrated in the accompanying drawing, in which:

` Figure lis a face view of a diaphragm embodying the invention.

Figure 2 is an edge view thereof.

Figure 3 is a magnified central cross section ofthe same.

In the drawing in which like numerals of reference indicate like parts in all of the figures, the diaphragm is shown composed of a central disk 1 of silk impregnated with an elastic varnish such as is used on the wings of aeroplanes. To each side ofthe disk l is suitably secured (by cement for eX- ample) one or more thicknesses 2, 3 of a compound of wool, cotton and wood pulp, such as a good quality of blotting paper for examplepressed to a thin edge 1n order to form a convexed center portion on each side of the disk l. The center portion is of less diameter than the disk 1 so as to leave a flange by which the diaphragm can be mounted in the sound box.

The needle holding arm of the sound box (net shown) may be-'connected to the geometric center of the diaphragm in the usual to each side of which are suitably secured' convexed disk-like bodies of lesser diameter than. that of the silk disk and waterproofed by an elastic varnish.

Ihave found from experience thatby the use of my invention, the tones produced are softer and more uniformly distinct than with the types of diaphragms now in common use and enables the sound ,box employing my diaphragm to be used with any kind of a horn without diminishing the advantageous features of the present invention.

I have also found that by the use of my improved diaphragm the harsh sounds and scratching noises usually produced are eliminated.

From the foregoing description, taken in connection withi'thel accompanying drawings, it is thought the construction and advantages of my invention will be clear to those skilled in the art to which it appertains. What I claim is:

A diaphragm composed of a vvarnished silk disk of uniform thickness throughout, a` plurality of smaller disks of a compound of wool, cotton and wood pul secured in superposed relation on each si e of said silk disk and progressivelydecreasing in diameter from the silk disk outwardly, said smaller disks each having their edges tapered to a knife edge whereby to provide convened surfaces on each side of the silk disk, and elastic waterproof varnish coating over said disks. Y

EDWIN F, MATTAUscH. 

